Work machines are generally provided with an operator station that has a seat located for good visibility of the area around the work machine while maintaining easy access to work machine and implement controls, such as joy sticks, steering wheels, buttons and the like. Arm rests and seat switches are commonly used as operational state sensors for work machines such as lawn tractors, skid steer loaders, integrated tool carriers, material handling machines, backhoe loaders and the like. As such, these switches are typically used to sense and detect when the machine operator is properly located in the machine prior to allowing movement thereof, and/or enabling or disabling various implement systems associated with the work machine. A typical switch/sensor arrangement of this type is disclosed, for instance, in U.S. Pat. No. 5,711,391. In other work machines, such as those associated with the agricultural industry, there is recognition that the operator may sometimes stand up in the operator station in order to get better visibility while traversing over ground being worked. U.S. Pat. No. 5,048,273 teaches an operator presence circuitry for a cotton harvester that maintains enablement of the work machine when a seat switch is open, such as when an operator is standing, if the transmission is in a drive mode, such as being out of a neutral gear.
Although these operator presence strategies can often times avoid annoying interruptions by misdetecting the absence of an operator, different work machines include different modes of operation requiring ever more sophisticated means of detecting an operator presence. If a work machine is being properly operated, but an interlock control system disables the work machine despite the presence of an operator, costly and annoying delays can occur. For instance, some work machines, such as motor graders, have an operation mode where the operator is present, but standing, while the transmission has zero output speed and is in a neutral gear. Such a condition may exist, for instance, when the operator is utilizing an inching pedal to smooth transition into a motion mode during precision grading operations.
The present disclosure is directed to one or more of the problems set forth above.